Computer systems allow users to create, view, and modify documents using various applications. A document is a collection of data in one or more files. For example, data in a document may represent text, graphic, spreadsheet, audio, video, meta-data about the document, or any combination of two or more of these.
Often, there is a need for multiple users to collaborate on a single document. This can be done by sending the document as an attachment to an email message. A first collaborator with the document initiates collaboration by attaching a copy of the document to an email message and sending the message to the other collaborators. The collaborators can then view and modify the document. A problem with this form of collaboration is coordinating the changes made by the various collaborators. For example, if A, B, and C are collaborators collaborating on a document which has been sent via email to B and C by A, then each of A, B and C will have a copy of the document. Each collaborator's copy of the document is separately edited by that collaborator. Collaborators may make conflicting changes in the document. Email may be exchanged between the collaborators, including comments on the collaboration. Email may also be used to send different versions of the document. At some point, changes made by the collaborators in their separate copies will need to be examined and conflicts reconciled to produce a single document which contains the results of the collaboration.
The need to resolve conflicts may be avoided using a common server for document collaboration. Collaborators have access (for example, via a network) to a document residing on a server. Using such a collaboration server can prevent conflicts, for example, by allowing only one collaborator at a time to edit the document. However, setting up a collaboration server can be difficult. A user must, at a minimum, identify a server, set access rights for collaborators, and upload the document to the server. Managing the collaboration server is also difficult. For example, it is difficult but desirable to allow new users access to the document, or to modify or remove access rights of existing collaborators. Additionally, it is difficult to encourage users to use the collaboration server when editing, rather than editing their individual copy.
Collaborators viewing and modifying a document on a collaboration server may be able to view in-document comments from fellow collaborators. For example, Microsoft®'s WORD® word processing software allows users to include comment data in documents which may be displayed in the margins of a document or in a separate pane. However, the exchange of comments other than those included in the document among collaborators is not supported by the collaboration server.